Windows 7 multi-screen problem

I've installed Fences on my laptop and it's been working fine.

Got home and hooked the laptop up to my external monitor ...

- Windows 7 correctly re-set my desktop so the external is my main display with start menu, etc.

- but Fences is still on my laptop display  

Is there someway to get the Fences over to the main display ?

Even better, a mode toggle, so there is one format for single display, another for dual ?

Cheers,

SteveC.